Fossil clues

Despite all the new dinosaur discoveries, many mysteries have not been solved. Why? Because almost all information has to come from ancient bones and footprints—fossils.

Just what are fossils? A fossil is an ancient dead animal or plant--or something left by them. Usually they are found buried in mud or sand that turned into rock. Now, thousands of years later, we find them in the layers of the earth. If the fossil is petrified, rock has replaced parts of the plant or animal.